


Eye for an Eye

by sinigmas (jaystrifes)



Category: Gravity Falls
Genre: Also a demon named Nyx, Alternate Universe - Canon Divergence, Bill adjusting to being mortal, Dip and Mabel have some cool powers, F/F, M/M, Magic, Older Pines Twins
Language: English
Status: In-Progress
Published: 2015-09-16
Updated: 2015-10-28
Packaged: 2018-04-21 01:26:22
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 5,708
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4809638
Author URL: https://archiveofourown.org/users/jaystrifes/pseuds/sinigmas
Summary: <blockquote class="userstuff">
              <p>The outcast demon Bill Cipher has one goal: to protect the Pines Twins. </p><p>In which Bill isn't as powerful as he'd like people to believe, Dipper and Mabel have more potential than they thought, Ford never made it out of the portal, and everybody must protect and sacrifice the things they love. The Nightmare Realm has some big plans. Be sure to know which side you're on.</p>
            </blockquote>





	1. Prologue

_“Why have you failed to collect another human soul in the appointed time, Cipher?”_

Bill blinks innocently, flexible black arms crossed over the top of his cane as he bobs in the air. “Well you see, chief –”

_“I prefer the simple truth to your mind games. Tell me.”_

A draft of hot, rank air buffets him from the dark, open chasm highlighted in oranges and reds by the luminous eyes of the monsters lurking within, all infinitely more powerful than Bill Cipher. The dream demon has been stuck in servitude to them for as long as he can remember.

Bill’s eye crinkles with amusement as he dodges the core issue again. “Truth, you say? That’s not very characteristic for a demon overlord, now is it?”

_“You waste your time handing out trivial tricks and hints, and lying even when it accomplishes nothing. Everything has a purpose, and I know this. That is the fundamental difference between your kind and mine.”_

He’s tempted to tell his boss to stop getting all self-righteous with him, but he thinks better of it. He’s in a tight enough spot as it is.

_“You’ve shirked your work for long enough. You’re clever, but you don’t deliver.”_

“Guess I’m not much of a delivery boy,” spills out before Bill can catch himself. Damn. He has to get better about limiting his sass.

_“You act like a human. Perhaps it’s about time you live like one. It will suit you.”_

The lesser demon is shocked into silence, which is rare. He always has something to say about everything. His steady motion in the air stills completely.

_“Yes, it will suit you nicely. Your usefulness has run its course, Bill Cipher.”_

“No, wait! You can’t do this!”

Bill’s whole form switches to a glowing, ominous red. Using that tactic in front of all the higher creatures, though, he feels a little ridiculous. It might intimidate mortals, but his superiors will just pass it off as an angry pink flush. Which might not be far from accurate, but shut up, there’s only so much a triangle can do.

Abstract features of a face appear in the void, a jagged grin with teeth filled in by the colors of deep space, speckled with the universes they’ve ripped apart. The set of accompanying eyes have no pupils, completely white. _“A pathetic jester like you does not tell me what I can or cannot do.”_ The voice has an echo to it, similar to his own, but with a feathery rasp behind it, silk sliding over steel.

Piece by piece, Bill’s shape falls away, glitching out of existence forever, until only his eye is left, his all-seeing eye that has never been closed. It’s forced shut, and he’s in the dark for the first time, truly in the dark, real emotions beginning to tear at him, overwhelming and choking, is this how humans feel? Is this fear?

He’s never known anything more excruciating, his very being torn to the molecular level and scattered too far apart to reassemble. He can feel his magic being stripped away, all the power he’s accumulated over the years, even if it’s nothing compared to a single one of the unseen claws that are shattering him down to the grain.

A howl of misery rings through the whole dimension. He doesn’t even register that it’s his own.

Finally there’s nothing left of Bill, but he is still there somehow, vaguely aware of pain. It’s materializing, condensing into a body – a human one. He’d rather be wiped from existence than stay this way forever.

_“If you wish to rejoin us, take their souls.”_

Bill doesn’t completely understand how it’s possible, but he's able to force out a “Who?”

_“You know who.”_

And as he falls to now-human knees, curse them, coughing up his stupid lungs and struggling to even breathe, he realizes that he does know. It’s been nearly four years since Bill last messed with the twins, and now, as the more powerful demon shoves an illusion through the frail barriers of his aching, vulnerable brain, _damn it_ ,  he knows exactly why Nyx wants them.

There’s only one thing to do.


	2. Kidnapping: The Birthday Present You Never Asked For

The morning of the twins seventeenth birthday begins much like any other: late, subdued, and peaceful. And also much like any other, it won't last.

Dipper blinks himself awake, in no hurry, letting his eyes adjust to the sunlight coming in through a gap in the drapes. Too warm, he unravels himself from the blanket and lays still, rejoicing in the quiet. The clock on the nightstand reads 10:32.

It’s been a long time since he’s slept up here with his sibling. A few years ago, he outgrew the small bed that used to be host to piles of scrolls and mystery novels and blacklights, and traded it out for the extra room after all, giving both of them more space and privacy to accommodate the dreadful awkwardness that is puberty.

The change in location hasn’t had as much of an impact on them as it would have five years ago, and they still spend plenty of time goofing around, but he has missed this. They spent a late night pre-celebrating together, as evidenced by the unwashed plates and empty cups on the floor, and conspicuous cheesy orange stains on his shirt. Disco Girl is still stuck in his head from jamming out to it with her.

He yawns and looks over to wish Mabel a good morning and happy birthday, and nearly jumps out of his skin when she cries out before he can speak. She jerks up, staring at Dipper without seeing, and her whole body spasms. In a heartbeat, he’s at her side, shaking her by the shoulders.

“Mabel! Mabel, what’s wrong?”

She twitches one last time, and falls limp, her brother’s arm cushioning her head as he eases her back down. “Dipper…?”

He takes a breath to quell the panic that surged into his chest. “Yeah. Yeah, it’s me, Mabel. Are you okay? What just happened?”

Mabel inhales deeply and licks her dry lips. Her mouth feels like it’s full of cotton. “I guess I just had a bad dream, but it felt so real, Dip. Like it really happened, like…like it’s gonna happen.” Her eyes search Dipper’s as she scrambles to get up, but he shushes her and makes her lie back down. “I think it was a vision.”

“Are you sure?”

“Are you not believing the words that are clearly coming out of my mouth?”

Dipper takes her hand and squeezes it by way of apology. He knows all too well how it feels to have his ideas dismissed as mere paranoia. “I’m not doubting you, but I just don’t understand. Why would you have a prophetic dream? And why now? I’ve never heard of anything like this in the journals.”

“Not everything is in the journals, dum-dum,” Mabel says, rolling her eyes. “Maybe we’re just special. Maybe it’s a superpower! What if you have one too? Try moving something with your mind!”

“We’re can't be that special. We’re not even from Gravity Falls.”

Mabel’s face falls, and quickly reddens with indignity. “How can you believe that?” She pushes him back and sits up, leaving him no room to stop her this time, one hand on his arm. “Do you not even want to know what I saw?”

In truth, he’s not sure why he feels so opposed to the idea, but it just isn’t right. He’s chased the supernatural in this town for years now, but he’s never been a part of it, and neither has Mabel. It won’t click, the notion that they might actually be. He can’t think of any logical explanation. Their parents aren’t magic or anything, that’s for sure, so it’s not inherited.

“I don’t want to fight with you on our birthday,” Dipper sighs. “Tell me your dream.”

“Vision!”

“Fine, your vision.”

“Well first there were a lot of fairies guiding me, and we fought off some unicorns again, and then we slid down this huge rainbow thing, and then –”

Dipper gets up and starts to leave, exasperated, but Mabel digs her sparkly nails into his palm. “Wait, bro, hear me out! I saw the _triangle guy_!” She emphasizes her point with fingers arranged around one eye, squinting up at him expectantly.

“You saw Bill,” Dipper says flatly, clearly unconvinced. “You were riding a rainbow and somehow you saw Bill. Have you been in the Smile Dip again?”

“That is an entirely unrelated question and I have the right to remain silent!” Mabel declares, crossing her arms and looking away. “Don’t believe me, fine. We’ll see what you say when he kidnaps you.”

Dipper huffs a laugh and walks out, heading for the stairs, but he pauses and looks at the window with its ominous red tint and suspiciously triangular markings. He’s had plenty of nightmares about the demon coming back to terrorize him, but none of them have come true in five years. It bugs him that he can’t explain why Bill suddenly lost interest in him, or the journals, or whatever he was really after, but Dipper knows he’s better off without any sort of involvement with him.

He’s overthinking this way too much. Mabel just had a weird dream, not a foreshadowing one. It’s not like he has anything to worry about. The creak of his sister’s feet on a board reminds him to keep moving, but just as he turns to go, a crack splits the windowpane. The latch snaps and the triangle etching divides in half, flying open. Pieces of rose glass break off as the window bangs against the wall violently. Standing in the bedroom doorframe, Mabel tries to warn him, but the words get stuck in her throat, overpowered with amazement that this is really happening, just like she saw.

Dipper is frozen with bewilderment, eyes wide, as a person leaps in. All he can identify is a head of wild blond hair before the breath is knocked out of him by an arm cinching around his waist, and as he finally regains his voice and starts yelling and kicking, his assailant only hoists him up over one shoulder and jumps out the window.

It’s a long way to the ground and the only thing he can think to do is squeeze his eyes shut, because he’s probably going to die, but then the wind catches them and, impossibly, they’re flying. He still can’t tell who it is; the back he’s beating a fist against is clothed in black and his fingers find no purchase in the slick material, and he can’t twist very far to get a look at the person’s face.

“Well well, long time no see, huh?” A chill runs down Dipper’s spine, dread pooling in his stomach. He’d know that parlance anywhere. Its pitch has been mellowed by human vocal chords, but the voice is the same at the core, no less headache-inducing than Bill Cipher’s triangle form. “Pine Tree.”

He shudders at the use of the nickname, his fist falling flat on his captor’s shoulder. Why did Bill have to come back now? Distressed, Dipper stares at the Mystery Shack receding in the distance, seeing his twin leaning out the window without really seeing.

“Dipper!” Mabel cries, hands clenched on the edge of the window, watching until Dipper and – was that supposed to be Bill in human form, or did he steal someone’s body again? – are out of sight. A splinter pokes her thumb, and the shards of glass scattered on the window seat where her knees balance have pricked her skin, but she barely feels it.

Sliding down to sit with her back to the open air, she puts her head in her hands. “Why didn’t you listen to me?” She heaves a sigh, but stops herself. “Nope, no time for moping. I’ve gotta do something. It’s my turn to save him.”

Mabel hurries back to her room to throw on a (questionably) clean sweater, pants, and hiking boots, and grab her trusty grappling hook. She has a feeling she’s going to need it. Equipped for battle, with her pig sidekick at her side, she allows herself a moment to pose heroically in the attic before she gets down to business.

“Now let’s see, where did that vision start?”

Mabel scratches Waddles’ ear, and he oinks pleasantly, but unhelpfully. She beams when she spots the tiny glowing figures outside. Fairies. Securing two prongs of the grappling hook to the edge of the roof, she scoops up Waddles and lets the rope carry their descent. As she scurries off into the forest with her miniature guides, Grunkle Stan flings open the twins’ bedroom door.

“Rise and shine, knuckleheads! Today’s the big day, am I right?”

There’s no answer. He squints at the unmade beds and the mess of junk food bags and cans left over from the previous night, rubbing his chin. After checking under the beds, in the closet, and even up on the ceiling, he determines he’s not going to be pranked. There’s no telling where those kids have gotten off to.

He shrugs and says, “Eh. More cake for me.”

Stan shouldn't worry about them as much anymore. They're old enough to handle themselves. He hopes.

**Notes for the Chapter:**

> "I'm going to update this soon," I say, as I don't.


	3. Cry for Help

There’s no reason for Bill not to drop Dipper right now, which is why he clings to the Bill’s shoulder and stays pressed tight again him, despite himself. His mind is racing and his heart feels like it might beat a hole through his chest. How is he supposed to react to being kidnapped by a dream demon that haunted him for one summer, other than with the obvious fear in his gut? Does he talk to him? Keep trying to fight him? There’s no correct way to handle this, and no journal to help him now.

Dipper takes a deep breath and lets it out shakily. If Bill wanted him dead, he could have let him fall miles ago.

“There you go, relax. I’m not gonna – whoopsie daisy!”

A cry tears from Dipper’s throat as he plummets a total distance of four feet before he’s back in Bill’s arms, quaking so much he’s at risk of falling again. Bill’s familiar, deranged laugh hurts Dipper’s ears, but for some reason, through all the adrenaline in his veins and the thumping of his heart, he almost wants to smile.

“Live a little, kid. You think I’d actually go through all the trouble of tracking you down and flying off with you only to drop you? You’re more useful to me alive. And more entertaining!”

“You’re a horrible person,” Dipper grumbles, his first words to Bill since he was abducted on his way to the bathroom. He’s still in his pajamas.

“Demon,” Bill reminds cheerfully, but Dipper has to wonder if that’s really the case. Whose body did he steal? Is it even stolen? He wants to know, but he doubts Bill would tell him the truth.

In this new position – bridal style, he realizes, and his face burns – he’s not sure what to do with his hands, so he crosses his arms tightly and does his best not to move too much for fear of being dropped again. The forest floor is nauseatingly far away. There’s nowhere to look but up at Bill. Dipper tunes out any morbid statements that might be thrown his way, absorbed in taking in the details of Bill’s defined jawline, and the dark tan skin contrasting fair feathery hair. Really, he’s not unattractive.

“Like what you see?” Bill asks, one eyebrow quirked. He was expressive enough as a one-eyed floating triangle, but that's nothing compared to this.

Dipper would like nothing more than to wipe that smug look from Bill's eyes, but he can only hide his red face behind his hands and refuse to acknowledge him. He still can’t adjust to the feeling of being in the air, with only Bill’s arms supporting him, and on a scale of comfort from 0 to 10, that’s a negative 20. Where is Bill even taking him? And why wasn’t that the very first question that crossed his mind? They’ve been flying for nearly thirty minutes. How long can Bill keep this up? Does his human body have any limits? Does he have any limits in general?

Before Dipper can work up the nerve to ask, Bill alights in a treetop, which wobbles and sways with their weight. He did not pick the ideal tree to land in. It’s a pine, the same as just about all of the other ones in these parts, and the branch is far too narrow for both of them. Trying not to look down, Dipper tucks himself into a bough and wraps his arms around the trunk to anchor himself. Now is not the time to show fear.

He scans the surrounding area for any hint at where he might be, but all he can see are more pines. When he listens more closely, he detects a vague rushing in the distance. “Are we close to the waterfall?”

“We could be.” Bill perches at the flimsy end of the branch, swinging on it like it’s not going to snap any minute now.

Dipper takes a moment to just stare at him, not sure what to ask first, and mildly confused by Bill’s choice of dress. “Please tell me you’re wearing something under that coat.”

His chest is exposed in a V, and only three buttons of the black coat are fastened, thankfully low enough to cover the important bits, but it doesn’t look like there’s anything but that. “You want me to start feeding you lies this early?”

Exasperated and more than a little embarrassed, Dipper averts his eyes. It’s time to start planning how he’s going to get himself out of this predicament, but Bill is such an unpredictable variable that escape might not be possible. Anything he does, he’s sure the demon can counter. He can’t be fooled by how laid back Bill is acting. 

There’s not much he can do when Bill scoots closer to him on the branch, getting up in his personal space. “Your human puberty has done wonders for you, kid.” Bill’s hand slides under Dipper’s chin, tilting his face from side to side. “You’re not the scrawny brat you used to be. Still a nerd, I’d wager, but I always liked that. Too smart to play dumb.”

Dipper’s not sure how to respond to that. His breath catches in his throat when the hand pushes up his brown hair and Bill inspects his forehead. Besides a mild smattering of acne, evidence that he hasn’t completely shaken the aforementioned puberty, there’s the constellation-shaped birthmark that earned him his nickname. “What’s this?”

“Didn’t notice it when you made me your ‘puppet’?”

Bill gives him a flat, unimpressed stare. “You still remember that? It’s been years, Pine Tree.”

“Don’t call me that!” Dipper jerks away from him. His teeth start chattering, even though it’s not cold, and there’s gooseflesh on his arms. He can’t control it. The demon’s name for him brings back a rush of bad memories and mixed emotions, and his eyes are stinging, his whole face red.

For a moment, Bill holds his gaze. It’s almost like he understands, like he does have a heart in there somewhere, like he might finally apologize or at least resolve not to continue tormenting Dipper.

But, of course, he ruins it and breaks into a grin, and takes a sing-song tone. “Pine Tree, Pine Tree, Pine Tree Pine Tree Pine Tree!”

Dipper presses his hands to his ears, even though it’s a childish tactic that doesn’t do much. He can’t find anything to focus on, nothing that will block out Bill’s antagonistic cheerfulness, and he seriously considers jumping off the branch. It physically hurts to listen, which isn’t rational, but that nickname, this asshole dream demon he thought he’d finally stop having nightmares about, it’s all too much and it hurts. What he tries to say comes out a scream.

“Stop it!”

Even the birds fall silent. Dipper hides his face against his knees, because as shaken up as he is he will not give Bill the satisfaction of seeing the tears streaked down his cheeks.

“Dipper! Dipper!”

The cry is distant, but he’d know the voice of the person he was born alongside anywhere. “Mabel,” he whispers to his skin, damp with tears. He’s never wished he had his hat more than he does now; he outgrew the one he wore when he was 12, but Stan gave him a new one a few sizes up and it doesn’t fit quite right but it’s seen many more adventures than its predecessor and has a habit of tilting over his eyes and he could really use that extra barrier between himself and Bill.

“Where you at Dippin’ Sauce?” Mabel calls out. She’s still far away, but at least close enough to hear him. Before Dipper can shout a response, Bill’s hand is over his mouth, preemptively muffling any sound. “Bro-bro?”

Bill is unbearably close to him, and even in his distress Dipper finds himself noticing small details like the color of his eyes, the faint scent of some exotic spice on him, and he nearly misses what Bill says. “Shooting Star’s out looking for you, huh? Good to know you two are still pals after all this time. Would’ve been a shame if someone had come between you in some alternate timeline. A real shame.”

“What are you talking about?” Dipper mumbles against the hand.

“Nothing of importance.”

Nonchalantly, Bill lifts Dipper up by the midriff, hoists him over one shoulder again like a sack, and jumps off the branch. Dipper takes one look at the ground between the trees they’re skimming through, blurred by speed, and decides to keep his eyes on Bill’s coattails whipping in the wind instead. Bill is preoccupied with flying, so Dipper takes the opportunity to yell for Mabel, only hoping she can hear him.

All of a sudden, their course swerves on a diagonal, and Dipper scrabbles at Bill’s back, making the situation worse by unbalancing them. They wobble in the air, and his heart is thumping about a thousand miles per minute, but somehow he ends up secure in Bill’s arms. Slowly, Bill regains his speed and altitude, adjusting his hold on the teenager. Dipper wonders what went wrong in the first place.

Bill’s flight falters once more, and Dipper knows something’s up. Is Bill finally reaching his limit? A look at his face reveals a clenched jaw, and sweat beading on his forehead, eyes nervously scanning for his destination. Dipper twists to look at the fast-approaching wall of water. He doesn’t have time to yell before they rocket through it and crash onto hard rock in a drenched heap.

Gasping for breath, Dipper lifts his head and shakes out his hair, spraying droplets all over the demon whose stomach he landed across. This may be his only chance to take the upper hand, while Bill is winded. If he can just find a weapon…even a sharp rock might do, now that he’s beginning to suspect how impaired by the human body Bill really is. He tries to push away, but Bill’s hand closes around his wrist, and he’s startled, not so much by being stopped but by the real skin against his own. It still feels weird to associate the demon with things like that.

“Why do you have a human form?” Dipper asks, quiet but still heard above the rush of the waterfall ten feet away.

Bill exhales slowly, gripping Dipper’s forearm harder to pull himself into a relatively upright position. “I’ll explain everything if you let me, Pi – Dipper.” As if to prove his good will, he lets go of him.

Dipper scrambles backwards, and nearly slips on the slick stone close to the waterfall at his back. The foamy spray keeps his shirt permanently damp. He looks over his shoulder, hoping against hope that Mabel has somehow found her way to him. On the edge of the waterfall, he glimpses an abnormally substantial rainbow arcing upwards with a recognizable figure skating on it, and it takes all he has to play it off and pretend he saw nothing because Bill is watching him like a hawk.

“I’m listening.”

Bill takes a minute to swallow his pride, adjusting the sodden sleeves of his coat, and, not for the first time, Dipper wonders why that’s all he’s wearing. How did he get into this state? Where has he been for all these years? “I don’t mean to hurt you or your sister this time. I need you.”

“So we’re still just going to end up being your puppets? Of course.”

“Kid, can you not shut up with your accusations for a minute? I need your help, your _willing_ help. I’m not in this flesh sack because I chose to be – it’s weird and uncomfortable and I don’t understand how it works and I need you to help me get back to normal.”

“Why would I do that? You seem less dangerous like this.”

Bill’s face twists so lividly that Dipper expects his eyes to go red, like the one in his triangle form did. He lurches forward, grabbing Dipper by the hair. “Make no mistake, I can still think of infinite ways to hurt you if you don’t comply. You, or Shooting Star.”

Dipper squeezes one eye shut against the prickling pain along his forehead. He’s pretty sure Bill might tear out a chunk of hair at this rate. But his fear is draining, leaving nothing but contempt for the demon-turned-human or whatever he is. “So now it’s a threat?”

“Dammit, Pine Tree, can you not tell that I have no other choice? You’re making this difficult.”

“Why me?” Dipper asks, mostly to himself, but he holds Bill’s gaze bravely. The prickling is turning into a weird warmth, spreading from his hairline down the spot where the birthmark is. “Why are you so obsessed with me, Bill? Out of all the people you could choose to haunt in this weird town, why me? How can I help you any more than, I don’t know, Tad Strange?”

“Because you –”

“Grappling hook!”

A three-pronged claw, the same one that’s saved the twins’ lives on more than one occasion already, shoots up into the cleft and catches on a rugged rock, and Dipper laughs out loud.

“On my way, bro!” Mabel calls from somewhere below. Dipper can’t imagine how she made it to a spot where the hook would actually reach all the way to the cave behind the waterfall, but she did it.

“Oh no you don’t.”

Bill lunges for the hook, but Dipper beats him to it. The heat on his forehead intensifies, almost like a fever, concentrated along the points that connect to make the constellation on his skin. It doesn’t hurt, but he glances up and sees his bangs are actually waving in the air, leaving the birthmark uncovered and glowing blue. Dipper nearly loses his focus, tempted to ask Bill what the hell is going on with him, but that would mean defeat.

As it is, Bill is just staring at him with his mouth half-open, like he knew to expect this but not to expect _this_. Dipper pushes his confusion aside and pretends he has this under control, and ethereal neon turquoise lines form from nothing to frame the demon’s figure perfectly, lifting him up into the air. By accident, Dipper moves his hand, which is also lined in the fluorescent light, and Bill is smashed backwards into the cave wall. Alarmed, he looks down at his palms, and shakes them out, trying to get rid of it, but he only succeeds in tossing Bill around like a ragdoll. When he sees the blood running down the side of Bill’s head, Dipper goes stock-still. There’s not much else he can do without risking seriously injuring Bill, and as much as he'd like to, he has too much of conscience for it.

He tries to think of something to cool down the feeling of power surging through his veins, power that honestly scares him because he can tell how . How does he even have this…this ability? No, no, that’s only stressing him out more. Dipper takes a few deep breaths, staring at his hands in the desperate hope that the glow will fade. He starts to clench one fist, until he realizes it’s the cause of the choking noise that comes from Bill. What is wrong with him? Why can’t he make this stop?

“A little help here?”

Mabel. The heat on his forehead subsides instantly, and with it, the lines. Dipper turns to pull her up, and into a hard hug before anything else. She pats his back as best as she can with being squashed.

“Ack, can’t breathe.”

Dipper steps back quickly and holds her by the shoulders. “I can’t believe you…never mind, we need to get out of here right now.”

Mabel grins and presses the button on the grappling gun to reel the hook back in. “No problemo.” Leaning out close to the waterfall, she closes one eye, aims along the cliff face up to the bridge spanning the gorge, and fires. “Boo-yah. Let’s go, Dippo.”

This was much easier when they were younger. Dipper has to stoop a little (looks like he ended up the alpha twin after all) to wrap his arms around Mabel, and she fumbles to get a grip on his other side. They look at each other, nod, and push off from the cave. In the moment before the grappling hook whisks them away, Dipper looks back at Bill, who is just starting to get up, looking miserable and wet and battered, but also grinning, for all that.

“See you next summer, _Dippo_ ,” he spits, and if he says anything else, it’s drowned out by the waterfall as the grappling hook’s path sends the twins careening through it.

Spitting water out, Dipper complains, “Not once, but twice, in one day.” He’s too relieved to really be miffed, though, and he and Mabel lock in a staring contest until they both burst out laughing.

“I am the real Spiderman!” Mabel crows into the wind, while Dipper glances down at the treetops far below and screams.

It’s a good thing his sister’s so strong. Not Grenda-level strong, but at least stronger than he’s ever been. Mabel is doing most of the work here, holding onto him with only one hand. Clinging to one another, they swing on the rope beneath the bridge, then back the other way, and Dipper realizes they really didn’t think this through.

“Uh, Mabel? How are we going to get down?”

“Hmm… Your turn to come up with a plan!”

Dipper needs to think of something, and fast. Not even Mabel can bear their weight forever, and the longer they dangle here, the more momentum they lose.

“We have to swing,” he decides. “We’re close enough to the cliff face that we can make it, as long as there are handholds.”

He reaches up to grab the rope in one hand, taking some the burden off Mabel. Arms locked around each other, they rock back and forth until they have the line picking up speed again, this time focusing on moving horizontally. After several wide arcs, Dipper feels the cliff brush against his back, and on the final swing he manages to anchor the two of them.

Thankfully, the cliff is easy to navigate, as long as he doesn’t think about the open air behind him. They shuffle up on a diagonal, towards the bridge, where Mabel unsnags the grappling hook from a steel support and reels it back in to the gun, blowing on the top of it like she just fired a pistol in the Wild West. Dipper laughs and shakes his head at her, then hugs her like he’ll never let go. She hugs back just as hard.

“I was really scared I lost you for a while there,” she mumbles to his shoulder, and he has no words to contradict it, so he doesn’t.

The moment would be best complemented with a sunset, but the sun is still high in the sky. Dipper judges it’s a little past noon, and his stomach agrees with a loud rumble. Mabel giggle-snorts and moves back to poke him right in the bellybutton.

Holding his belly to avoid another attack, Dipper sticks his tongue out at her. “You’re completely soaked, Mabes.”

“So are you! Your pajamas are ruined, dude.”

“I know,” Dipper groans. “Cipher owes me a new pair of fuzzy Pokémon pants.”

“Told you so,” Mabel hums as they head through the tunnel and towards home. Oinking heralds a green Waddles’s arrival. She leans down to pet him as he trots alongside them, and Dipper wants to question the pig’s sudden change in color, but there are more important things to talk about.

“About what?”

“Triangle guy. Even though he wasn’t really a triangle this time.”

“Oh.” Dipper rubs the back of his neck. “Yeah. Yeah, you were right. I’m seriously sorry I doubted you for even a second. I guess I just…I was starting to lose my belief in all this stuff, I’ve gotten so used to it. I was ready to grow up and stop chasing fairy tales. I guess I didn't even want to believe we could be special. I’m sorry, Mabel.”

“We’re definitely special, magic or no.” Mabel jostles him with her shoulder friendlily. “And hey, you were kinda right too. We shouldn’t have been fighting on our birthday, Dippin’ Dot.”

“Well, I think we’ve still got a few hours of birthday left in Gravity Falls. Let’s go make the most of them.”

Dipper offers her his arm, and she links hers through it, and the dripping, newly-turned-seventeen-year-old twins set off for home.

“So, I guess you got to ride that rainbow you were talking about. And Waddles is green now?”

“Oh, it’ll wear off. Probably. It’s a long story.”

“Well, we’ve got a long walk.”

**Notes for the Chapter:**

> I said I'd update this like, a month ago, but I'm an unreliable excuse for a writer. Sorry.  
> In other news, Bill is an ass in the beginning, but who's surprised?


End file.
